L10 - Blood Flashcards

1
Q

What are blood group antigens?

A

Proteins on the surface of red blood cells that determine blood donor compatability

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2
Q

What are the 2 major blood group systems?

Give an example of a less common system

A

ABO system and Rhesus (Rh) system

Kell, Kidd, Duffy, MNS

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3
Q

In the ABO system, what is H substance?

What is its chemical composition?

A

The base of A and B antigens

Glucose > galactose > N-acetylglucosamine > galactose > fructose

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4
Q

What are the major groups according to the ABO system?

A

A, B, AB, O

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5
Q

What converts H substance into A antigen?

How is this done?

A

Enzyme product of the A gene adds an N-acetylglucosamine to the distal galactose, alongside the attached fructose

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6
Q

What converts H substance into B antigen?

How is this done?

A

Enzyme product of the B gene adds another galactose to the distal galactose, alongside the attached fructose

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7
Q

What are the major characteristics of blood group A in terms of antigens and antibodies present?

A

A antigen present, anti-B antibodies

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8
Q

What are the major characteristics of blood group B in terms of antigens and antibodies present?

A

B antigen present, anti-A antibodies

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9
Q

What are the major characteristics of blood group AB in terms of antigens and antibodies present?

A

Both A and B antigens present, no antibodies

universal receiver

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10
Q

What are the major characteristics of blood group O in terms of antigens and antibodies present?

A

No antigens present, both anti-A and anti-B antibodies

universal RBC donor, can only receive O blood

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11
Q

What are the most common ABO blood groups in the UK and North America?

A

UK - O

America - A

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12
Q

What are the main antigens in the Rhesus (Rh) blood system?

Which one is of most clinical significance?

A

C, c, D, E, e

D

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13
Q

How is a sample’s Rh group determined?

A

Positive - D antigen present

Negative - No D antigen

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14
Q

What is the most common Rh group?

A

Positive

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15
Q

What happens to the red blood cells of a type B sample when transfused into a patient who is type A?

A

The patient’s anti-B antibodies bind to the new blood cells and lyse them

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16
Q

How are risks from donating blood reduced?

4

A

Donor screening, testing for infections, correct storage, protocols for the use of blood products

17
Q

How is a patient’s blood group determined?

A

Add agglutinating anti-A and/or anti-B to patient red blood cells

18
Q

What is the back group in blood typing and how is it determined?

A

Whether the patient has anti-A or anti-B antibodies that could affect the donor’s blood

Add RBCs with A or B antigen to patient sample

19
Q

How is Rh blood typing carried out?

A

Add agglutinating IgM anti-D to sample, or add IgG anti-D alongside a Coombs test

20
Q

What are the two types of Coombs (anti-globulin) tests used in haematology?

A

Direst and indirect

21
Q

What is the difference between a direct and indirect Coombs test in terms of what they are used for?

A

Direct - detects Ig bound to RBCs

Indirect - detects non agglutinating Ig against D antigen in serum

22
Q

What is the difference between a direct and indirect Coombs test in terms of how they are carried out?

A

Direct - add anti-human Ig to sample, look for agglutination

Indirect - incubate sample with Rh+ RBCs, wash, then add anti-human Ig to see if antibodies from patient serum has bound

23
Q

Give an example of when a direct and indirect Coombs test would be carried out

A

Diagnose haemolytic disease of the newborn in a Rh- mother and Rh+ foetus

24
Q

How would a direct Coombs test be used to test for haemolytic disease of the newborn?

A

Test baby’s sample for bound maternal anti-D antibodies

Diagnoses condition

25
Q

How would an indirect Coombs test be used to test for haemolytic disease of the newborn?

A

Test mother’s sample for unbound anti-D antibodies that could enter the baby’s blood stream at delivery

Can prevent the disease